Descaling spray nozzle assemblies are extensively used in steel processing for directing a wide thin line high pressure spray onto the surface of steel slabs for penetrating and removing iron oxide scale buildup on the surfaces prior to rolling and subsequent processing of the steel. In such spraying systems, it is desirable that the high pressure liquid discharge be as thin as possible for effecting maximum impact pressure and penetration of the scale. It also is desirable that the distribution of the liquid discharge be uniform across the width of the spray pattern. Heretofore, the liquid distribution often is unevenly reduced toward the opposed ends of the discharging spray pattern, which reduces impact forces and adversely affects the uniformity of the spray penetration and scale removal.
Such descaling spray nozzle assemblies typically comprise a tubular body, sometimes referred to as a high impact attachment tube, formed with a liquid flow passageway that tapers inwardly in a downstream direction for accelerating the liquid flow, a strainer affixed to an upstream end of the tubular body for straining particulate matter and scale from recycled steel mill water typically used in such descaling processing, and a carbon insert spray tip mounted at downstream end of the tubular body having an elongated liquid discharge orifice for forming and directing a flat spray discharge pattern. High pressure liquid directed through the strainer can incur considerable turbulence, which in turn can adversely affect the uniformity and impact force of the discharging spray.
For reducing turbulence and straightening the liquid flow stream through the high impact attachment tube prior to passage through the spray tip, it is known to provide a vane having a plurality of radial vane elements immediately downstream of the strainer, which effectively defines a plurality of circumferentially-spaced laminar flow passages. Since such vane can only have a limited number of radial vane elements, such as on the order of five, it sometimes is incapable of adequately moderating highly turbulent flow streams, such as from turbulence incurred by high pressure liquid entering the strainer in a radial direction and then abruptly changing direction for passage through the strainer and high impact attachment tube. Efforts to provide such a vane with a greater number of radial vane elements have not been acceptable because the additional vanes result in a corresponding reduction in size of the laminar flow passageways, which restricts fluid passage, creates undesirable pressure drops, and in fact increases turbulence.
Such descaling spray nozzle assemblies also are relatively expensive to manufacture, since the components must be precisely formed and assembled in order to achieve acceptable performance. Indeed, without precise radial orientation of the elongated spray tip discharge orifice with respect to the radial vane elements of the liquid straightening vane, the uniformity of the discharging spray pattern again can be adversely affected.